Expanded synthetic calcium silicates

Abstract

The invention relates to expanded synthetic calcium silicates, particularly of a kind having a white or other pure color.

We claim: 
     
       1. A hydrothermally hardened silica concrete of the reaction product of a CaO component and an SiO 2  component, characterized in that the SiO 2  component is a previously expanded synthetic calcium silicate comprising beads having a sphere-like structure, having an external sealing skin and numerous small non-intercommunicating air bubbles in the interior of the bead separated by thin walls, the concrete having a raw density of 0.7 to 1.4 g/cc, the CaO component being present in the proportions of about 5 to 25% and the expanded synthetic calcium silicate in the proportions of about 10 to 95% by weight. 
     
     
       2. The silica concrete of claim 1, wherein said expanded calcium silicate is colored. 
     
     
       3. The silica concrete of claim 1 wherein the expanded calcium silicate has the following composition: 20 to 55% by weight of CaO   27 to 60% by weight of SiO 2     0 to 27% by weight of Al 2  O 3 .   
     
     
       4. The silica concrete of claim 1, wherein said expanded calcium silicate has the following composition: 30 to 50% by weight of CaO   44 to 55% by weight of SiO 2     4 to 14% by weight of Al 2  O 3 .   
     
     
       5. The silica concrete of claim 1, wherein said expanded calcium silicate has the following composition: 33± 4% by weight of CaO   55± 3% by weight of SiO 2     11± 3% by weight of Al 2  O 3 .